June 21, 2012

The passive and active contractile properties of the neurogenic, underactive bladder.

The passive and active contractile properties of the neurogenic, underactive bladder.:
The passive and active contractile properties of the neurogenic, underactive bladder.
BJU Int. 2012 Jun 19;
Authors: Young JS, Johnston L, Soubrane C, McCloskey KD, McMurray G, Eccles R, Fry CH
Abstract

What's known on the subject? and What does the study add? Detrusor underactivity is highly prevalent, particularly in the elderly. It is assumed to result from detrusor failure, although detrusor contractility is often derived from urodynamics studies. Given that detrusor pressure and force are not proportional and urodynamics cannot identify the basis of the pathology, we produced a neurogenic animal model with a highly-compliant bladder and studied detrusor muscle properties, aiming to increase our understanding of the underlying pathology. Highly compliant bladders were characterized by reduced passive wall stiffness and stretched detrusor muscle strips exhibited an enhanced rate of relaxation. These detrusor strips displayed spontaneous contractions that were of greater amplitude (expressed as a ratio of bladder wall stiffness) than those of strips from sham-operated animals; spontaneous contractions increased in amplitude when stimulated by an agonist. These data imply that compliance is not the result of a reduction of detrusor contractility; we hypothesize that altered matrix properties reduce the magnitude with which force can be generated to void the bladder. OBJECTIVE: •  To characterize passive and active changes in detrusor activity in a highly compliant bladder. MATERIALS AND METHODS: •  Bladders from adult female Sprague-Dawley rats were used 5 weeks after lower thoracic (T8) spinal cord transection or a sham-operation. •  Passive wall properties were assessed by pressure-volume relationships from whole bladders and the tensile response of bladder strips after a rapid (<0.5 s) stretch. •  Active properties were assessed from the frequency and amplitude of spontaneous contractions of bladder strips, and their response to the inotropic TRPV4 agonist GSK1016790A. RESULTS: •  Passive bladder wall stiffness of SCT bladders was significantly reduced compared to that of the sham-operated control group (N= 6 and 8, respectively) and SCT bladder strips relaxed more quickly than those from sham-operated rats. •  The frequency of spontaneous contractions was reduced in SCT rats, and their amplitude, expressed as a ratio of bladder wall stiffness, was greater than in sham-operated rats. •  GSK1016790A (0.1 µm) significantly increased amplitude in strips from both sham-operated and SCT groups. CONCLUSIONS: •  There is no evidence of contractile failure in a highly-compliant bladder. The observations of reduced passive bladder wall stiffness and an enhanced rate of stress relaxation lead to the conclusion that increased compliance is marked by altered matrix properties that dissipate muscle force, thereby generating low pressures. •  Contractile agonists may be effective for improving bladder function in detrusor underactivity.


PMID: 22712666 [PubMed - as supplied by publisher]

June 7, 2012

Prevalence and Clinical Features of Detrusor Underactivity among Elderly with Lower Urinary Tract Symptoms: A Comparison between Men and Women.

Prevalence and Clinical Features of Detrusor Underactivity among Elderly with Lower Urinary Tract Symptoms: A Comparison between Men and Women.:
Prevalence and Clinical Features of Detrusor Underactivity among Elderly with Lower Urinary Tract Symptoms: A Comparison between Men and Women.
Korean J Urol. 2012 May;53(5):342-8
Authors: Jeong SJ, Kim HJ, Lee YJ, Lee JK, Lee BK, Choo YM, Oh JJ, Lee SC, Jeong CW, Yoon CY, Hong SK, Byun SS, Lee SE
Abstract

PURPOSE: To identify the prevalence and clinical features of detrusor underactivity (DU) in elderly men and women presenting with lower urinary tract symptoms (LUTS).

MATERIALS AND METHODS: We reviewed 1,179 patients aged over 65 years who had undergone a urodynamic study for LUTS with no neurological or anatomical conditions. DU was defined as a bladder contractility index <100 and a maximal flow rate (Qmax) ≤12 ml/s combined with a detrusor pressure at Qmax ≤10 cmH(2)O for men and women, respectively.

RESULTS: Of the patients, 40.2% of men and 13.3% of women were classified as having DU (p<0.001). Types of clinical symptoms were not significantly different between patients with and without DU. In men, whereas the prevalence of bladder outlet obstruction (BOO) was constant across the age spectrum, the prevalence of DU and detrusor overactivity (DO) increased with age, and 46.5% of men with DU also had DO or BOO. In women, the prevalence of DU also increased with age, and the trend was more remarkable in women aged over 70 years. DU was accompanied by DO or urodynamic stress urinary incontinence (USUI) in 72.6% of the women with DU. Women with DU were found to have lower cystometric capacity and exhibited a greater incidence of reduced compliance than did women without DU.

CONCLUSIONS: DU was a common mechanism underlying LUTS in the elderly population, especially in men. One half of the men and three quarters of the women with DU also had other pathologies such as DO, BOO, or USUI.


PMID: 22670194 [PubMed - in process]

June 4, 2012

Persistent vesicourethral dysfunction following radical surgery for rectal carcinoma: urodynamic features and potential abatement with modified sphincterotomy (radical transurethral resection of the prostate).

Persistent vesicourethral dysfunction following radical surgery for rectal carcinoma: urodynamic features and potential abatement with modified sphincterotomy (radical transurethral resection of the prostate).:
Related Articles
Persistent vesicourethral dysfunction following radical surgery for rectal carcinoma: urodynamic features and potential abatement with modified sphincterotomy (radical transurethral resection of the prostate).
Int J Urol. 1998 Jan;5(1):39-43
Authors: Mitsui T, Shinno Y, Kobayashi S, Matsuura S, Shibata T, Ameda K, Koyanagi T
BACKGROUND: Vesicourethral function returns after radical rectal surgery during the first year but rarely progresses after 1 year. We examined the urodynamics of patients whose voiding dysfunction remained after 1 year, and treated several with a modified sphincterotomy procedure similar to radical transurethral resection of the prostate. METHODS: We analyzed the urodynamic features of vesicourethral dysfunction in 16 male patients with persistent voiding dysfunction for more than 1 year following radical surgery for rectal carcinoma. Seven patients elected to undergo radical transurethral resection of prostate (radical TUR-P) for the relief of their persistent voiding dysfunction. RESULTS: The mean bladder volume at the first desire to void was 210 mL, the mean maximal bladder capacity was 343 mL, and the mean vesical compliance (Cves) was 27.1 mL/cm H2O. All patients demonstrated either vesical denervation supersensitivity (Vds) or uninhibited contraction. The mean maximal urethral closure pressure was 43.9 cm H2O, and urethral denervation supersensitivity was found in 77.8% (7/9), and sphincter dyssynergia in 66.7% (6/9) of patients. After radical TUR-P, 5 patients became free from the use of self-catheterization, 1 patient had a reduced residual urine rate, and 1 patient was unchanged, but no patient noted a change in urinary control. CONCLUSION: Urethral dysfunction after radical rectal surgery was caused by failure of the bladder to empty along with an underactive detrusor. Radical TUR-P was effective in restoring voiding function in a selected group of these patients.
PMID: 9535599 [PubMed - indexed for MEDLINE]